Pinthong Piriya, Klongklaew Phongsathon, Praserthdam Piyasan, Panpranot Joongjai
Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand.
Bio-Circular-Green-economy Technology & Engineering Center, BCGeTEC, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand.
Nanomaterials (Basel). 2021 Jun 25;11(7):1671. doi: 10.3390/nano11071671.
Zn/Cu electrocatalysts were synthesized by the electrodeposition method with various bath compositions and deposition times. X-ray diffraction results confirmed the presence of (101) and (002) lattice structures for all the deposited Zn nanoparticles. However, a bulky (hexagonal) structure with particle size in the range of 1-10 μm was obtained from a high-Zn-concentration bath, whereas a fern-like dendritic structure was produced using a low Zn concentration. A larger particle size of Zn dendrites could also be obtained when Cu ions were added to the high-Zn-concentration bath. The catalysts were tested in the electrochemical reduction of CO (CORR) using an H-cell type reactor under ambient conditions. Despite the different sizes/shapes, the CORR products obtained on the nanostructured Zn catalysts depended largely on their morphologies. All the dendritic structures led to high CO production rates, while the bulky Zn structure produced formate as the major product, with limited amounts of gaseous CO and H. The highest CO/H production rate ratio of 4.7 and a stable CO production rate of 3.55 μmol/min were obtained over the dendritic structure of the Zn/Cu-Na200 catalyst at -1.6 V vs. Ag/AgCl during 4 h CORR. The dissolution and re-deposition of Zn nanoparticles occurred but did not affect the activity and selectivity in the CORR of the electrodeposited Zn catalysts. The present results show the possibilities to enhance the activity and to control the selectivity of CORR products on nanostructured Zn catalysts.
采用电沉积法，通过改变镀液组成和沉积时间合成了锌/铜电催化剂。X射线衍射结果证实，所有沉积的锌纳米颗粒均存在(101)和(002)晶格结构。然而，从高锌浓度镀液中获得了粒径在1-10μm范围内的块状（六方）结构，而在低锌浓度下则生成了蕨状树枝状结构。当向高锌浓度镀液中添加铜离子时，也可以获得更大粒径的锌树枝晶。在环境条件下，使用H型电池反应器对催化剂进行了CO电化学还原（CORR）测试。尽管尺寸/形状不同，但在纳米结构锌催化剂上获得的CORR产物在很大程度上取决于它们的形态。所有树枝状结构都导致了较高的CO生成速率，而块状锌结构则以甲酸盐为主要产物，气态CO和H的量有限。在-1.6 V（相对于Ag/AgCl）下进行4 h的CORR过程中，Zn/Cu-Na200催化剂的树枝状结构实现了最高的CO/H生成速率比4.7和稳定的CO生成速率3.55μmol/min。锌纳米颗粒发生了溶解和再沉积，但并未影响电沉积锌催化剂CORR的活性和选择性。目前的结果表明了提高纳米结构锌催化剂CORR活性和控制CORR产物选择性的可能性。
